Ad Widget

Collapse

Announcement

Collapse
No announcement yet.

a simple question....

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • a simple question....

    I have a simple question for someone (s) to consider. If a 5Y3 rectifier is inserted without proper indexing into its socket what might be the residual damage?
    I purchased a Harmony H-304 from a music store a few years ago. It did not pass signal but hummed rather loudly. I have been working on it , off and on, for the past years. It is a single-ended amp with a single 6V6 output tube. It also uses a 6BF6 preamp tube and a 6AT6 driver. When I bought the amp, the 5Y3 rectifier had no index pin (it had been snapped off) and the tube was installed without regard for the proper indexing.
    Over the years I have been able to test the tubes, replace electrolytics and drifted resistors. I have been able to get it operable but the output was weak (compared to a Harmony H-304A I recently purchased).
    Since almost 100% of the passives have been replaced, is it possible that the mis-indexing of the 5Y3 did some damage to the output transformer? Thank you for your thoughts!

  • #2
    Usually it just blows the tube or blows the fuse.

    Comment


    • #3
      Time for a new 5Y3, and some voltage readings?
      Don't believe everything you think. Beware of Rottweiler. Search engines are free.

      Comment


      • #4
        The aforementioned 5Y3 is long since gone. The owner of the store tried to persuade me that they were all made that way. I took the amp home and replaced it ASAP. The amp always sounded good but lacked volume. When I got the newer version (H-304A) I went through that amp and found it to be very similar. When I got the 304A up and running, it sounded much better than the 304. I checked voltages and they were almost identical. Finally, I touched the outer paper wrapping of the output transformer to see if it was getting hot and the amp began to buzz loudly. I shut it off and tried to check it again but it still hummed. the only thing I can attribute it to is that the OT was on the verge of shorting out and all it took was a touch. I replaced the OT with one from a Valve JR (5.2K primary/8ohm secondary) and the amp sounds every bit the equal of the later version. I have all the volume and a lot fuller tone with this donor OT.
        I guess now it is clear why I initially asked the question about a mis-indexed 5Y3 possibly causing an OT to fail. As I mentioned before, nearly all the resistors and all the caps have been replaced in my quest to track down the problem. I did not have any voltage discrepancies to warn me of an impending failure...only the weak output.

        Comment

        Working...
        X